Mission cycle fatigue testing of a [0]8 SCS-6/Ti-6A1-4V composite was performed. The mission cycle simulates the stress-temperature-time profile in a ring-reinforced impeller of a turboshaft engine. The cycle has a fourteen minute period and attains a peak stress and temperature of 1100 MPa and 427‡C respectively. A fatigue life of 9,528 cycles was achieved. While this life was less than the design goal, 15,000 cycles, a moderate increase in fiber content coupled with a small decrease in peak stress or temperature would probably achieve the stated design goal.